Head of Xbox Phil Spencer wants Microsoft's next console to offer a "substantial" upgrade over the current Xbox One, suggesting that it could be more than just Xbox 1.5.

Speaking at Microsoft's Build 2016 Developer Conference last week (as reported by Game Informer), Spencer revealed that he isn't a fan of the term 'Xbox One and a half' that's been adopted by fans and press since suggesting that the company has plans to launch a more powerful Xbox One, instead stating that "if we’re going to move forward, I want to move forward in big numbers".

"I don't know anything about any of the [PS4K] rumours that are out there," he said, "but I can understand other teams’ motivations to do that. For us, our box is doing well. It performs, it’s reliable, the servers are doing well. If we’re going to go forward with anything, like I said, I want it to be a really substantial change for people – an upgrade."

Spencer's comments follow a month after he revealed that fans "will see more hardware innovation in the console space than we've ever seen.

"We'll see us come out with new hardware capability during a generation and allow the same games to run backwards and forward compatible because we have UWAs (Universal Windows Applications) running on top of UWP (Universal Windows Platforms). It allows us to focus on hardware innovation without invalidating the games that run on that platform.

"We can effectively feel a little bit more like what we see on PC where I can still go back and run my old Quake and Doom games, but then I can also see the best 4K games coming out," he continued. "Hardware innovation continues and software takes advantage. I don't have to jump generation and lose everything I played before."

The comments led to speculation that the firm may have plans to release a more powerful Xbox One. But last week's comments suggest that the firm may have plans to do more than that, possibly releasing a significantly more powerful console far sooner than expected, and potentially marking the arrival of the next generation of consoles.

Xbox One launched in November 2013 and, while performing better than Xbox 360 at the same point in its lifecycle, has failed to sell as many units as rival PS4. Figures revealed by EA in January suggest that Xbox One sales roughly stood at around 19 million, with PS4 close to 36 million.

Back in September 2013, former Microsoft exec Phil Harrison said that the Xbox One would have "more than a ten-year journey".